A recent body of work on the TacTip sensor used here focused on mitigating the effects of motion-dependent shear during tactile servo control to slide around planar shapes [1]}, [2]} and complex 3D objects [3]}, [4]}. The shear-dependence problem was addressed in three studies that used a deep convolutional neural network to predict pose by training insensitivity to shear into the prediction network [1]}, [3]}, [4]}. While effective, this has a drawback that procedures for learning shear-invariance needs to be introduced into the training for each individual task, and thus would not generalize easily to new tasks. Another study did not use deep learning, but instead dimensionally reduced the tactile data [2]}, where the the pose components naturally separated from the shear components.
